Heretofore, for example, a flow rate control valve has been known, which is connected through piping to a fluid pressure device such as a cylinder or the like, and which is capable of controlling the operation of the fluid pressure device by adjusting the flow rate of a fluid supplied to and discharged from the fluid pressure device.
With this type of flow rate control valve, for example as disclosed in Japanese Laid-Open Patent Publication No. 2001-141090, a tubular shaped main valve body is installed in a central portion of a cylindrical body having a linear form, the main valve body being substantially perpendicular to the longitudinal direction of the cylindrical body.
A throttle valve for adjusting the flow rate of the fluid flowing inside the cylinder body is threaded in a through-hole of the main valve body such that the throttle valve is movable back and forth. The flow rate of the fluid is adjusted by the back-and-forth operation of the throttle valve.
The above-mentioned flow rate control valve generally is disposed at a position separated from the fluid pressure device such as a cylinder or the like, and is remotely controlled. Further, often, a manifold is used, to which multiple devices are arranged in communication therewith. In this case, it is difficult to confirm operations of all of the flow rate control valves from among a plurality of flow rate control valves. Further, since such flow rate control valves frequently are formed with lateral (left/right) symmetry, it is difficult to confirm the flow direction of fluids from the exterior of the flow rate control valves.